Flushing oil



- Patented June 6, 1939 UNITED STATES FLUSHING 01L Robert P. Russell, Elizabeth, N. J., assignor to Standard Oil Development Company, acorporation of Delaware No Drawing. Application September 28, 1934,

Serial No. 745,937

5 Claims.

This invention deals with the use of superior flushing oils and the manufacture thereof. More specifically, it concerns the production of engine conditioning flushing oils, and will be more clear- 5 1y understood from the'following description.

The usual flushing oils of commerce are mainly employed to remove dirt and sludge from the engine, so as to prevent contamination of the fresh lubricating oil to be added. They comprise oils'having little or no lubricating power, such as kerosenes, gas oils and the like. Heretofore, the solepurpose of the .fiushing oil has beento remove sludge deposits from the engine and no attempts have been made to use a flushing oil which will condition the engine so as to prepare the hot metal surfaces to resist deterioration of the oil.

It is well known that metals such as iron,

nickel, etc., act as oxidation catalysts, thereby 0 causing rapid deterioration of the oil. When this occurs, the engine surfaces become coated with undesirable materials decreasing the eificiency and increasing the wear of the engine. Engineconditioning contemplates an effect on the en'- gine metal surfaces such that the catalytic acceleration of lubricating oil deterioration thereby is inhibited or stopped and possibly such that an opposite effect is produced, in which the metal surfaces become active to inhibit ordinary de- 0 terioration in the engine. Engine-conditioning agents, whatever may be their mode of operation,

have been found to decrease formation and de- I position of oxidation and other carbonaceous oil products, and in keeping suchproducts of deterioration in suspension in the oil or as a flocculated mas's in the crankcase, not only increase efiiciency of the engine but also its life. The flushing oils prepared according to this invention are'made engine-conditioning by the addition of materials such as colloidal lead and other can be noticed with the naked eye, yet such treatment has a profound eflect in reducing the formation of carbon or sludge, reducing wear in the engine and increasing the life of the lubricant used. On the other hand, electro-plated 5 surfaces generally become loosened in a short while, and are not very effective, possibly due to porosity, the type of film obtained, etc.

These engine-conditioning materials may be used in any combination desired, preferably in a concentration of 2 to 5% in the flushing oil base.

-In many cases 0.01 to 0.1 or 1% has been'found satisfactory, while in many'instances over 2%, say 5% or even 10% or more have been found desirable, depending on the particular agent used, the type of lubricating oil to be added to the engine, the type of engine, and other factors.

Any flushing oil base is suitable for carrying these engine-conditioning agents, although it is preferable to employ oils. of low viscosity suchas 20 to or seconds Saybolt at 210 F. and especially oil solventshaving a kauri butanol value above 20 and, better yet, above 30 or 40. The materials described in application Serial No. 729,234, filed by G. L. Matheson and R. Rosen 5 on June 6 1934, have been found very suitable for the purposes herein set forth.

In carrying out this invention, the engineconditioning agents are dissolved or dispersed in the desired flushing oil base stock. A dispersing and/or stabilizing agent may be advantageously added to prevent settling of these materials. The blend so prepared is then added to the en gine, the oil of which has been previously drained, and the engine is allowed to run for 5, 10, 15 orv even 30 minutes or longer until the lubricating oil has been substantially replaced by the flushing oil. The latter is then drained out and the lubricating oil to be used is added. The flushing oil can be added hot, say at a temperatureof to 300 F. or higher in order to shorten the time of flushing. .It is also often advantageous to flush the engine first with an ordinary flushing oil so as to remove the greater part suspended sludge and solid particles, and then flush with the flushing oil made according to this invention, to recondition the engine. By this means it is possible to save the drainings of the latter step for further flushing purposes, with or without a preliminary purification by filtration, etc. The usual period of operation between flushings depends on the type of oil, and also the engine, but it is found that the effect produced by the present improved flushing oil persists and ordinarily it is possible to safely extend the mileage between oil changes. It is desirable to use the flushing oil between all changes but in many instances the improvement is suificiently persistent so that the flushing may be employed only after two or three oil changes.

The following examples are submitted to show the variety of phases embraced by this invention:

This blend is heated to 200 tion into the engine,

Example 4 F. before introduc- Percent Tetraphenyl tin l. Edeleanu extract (25-35 viscosity Saybolt at 210 F.) 99.0 Two samples of flushing oil containing 0.2% triphenyl bismuth were 'kept in a steel cone (by stoppering the outlet), one for a period of 3 days, the other for 3 hours, at a temperature of about 200 F'., corresponding to maximum crankcase temperature. Subsequently the flushing oilwas run out of the cone but no'visible change was observed. A sample of a lubricating oil run immediately afterwards on this cone at 250 C. without any cleaning gave a marked reduction in deposit as shown by the data given below: i

on Total cone deposit Gmc. Lubricating oil before flushing 0. 51 Lubricating oil after flushing with triphenyl bismuth as described above (3 hours) 0. 43 Lubricating oil after flushing with triphenyl bismuth as described above (3 days) 0. 14

A sample of flushing oil containing 0.2% triphenyl bismuth was run over the steel cone for a period of five minutes at 250 C. and then lubricating oil was run on the cone at 250 C. without any cleaning up of the cone surface. In another test, the same flushing oil was run over the cone for a period of 15 minutes at 250 CI and. then the lubricating oil run without any cleaning up of cone surface. The results obtained ascompared with the data on the lubricating oil run on a clean cone at 250 C. are given below:

These engine-conditioning agents may be used in conjunction with oiliness agents, sludge dispersers, oxidation inhibitors, soaps, pour inhibitors, thickeners capable of raising the viscosity and/or viscosity index of oils, also dyes, organic solvents, etc. v

Various modifications maybe made in carrying out this invention, and it is not intended to limit the scope of the description or examples,.but only by the-following claims in which it is intended to cover the invention as broadly as the prior art permits. i

. I claim:

1. A flushing oil comprising a petroleum oil of the class consisting of kerosene and gas oil, and 0.01 to 10%- of a metallo-organic compound capable of reducing the cone deposit of the lubricating oil subsequently employed in the engine.

2. A flushing oil comprising a petroleum oil of the class consisting of keroseneand gas oil and of an oil soluble metallo-organic derivative of the elements of the group consisting of lead, bismuth, arsenic, antimony, tin and zinc.

3. A flushing oil comprising a petroleum oil solvent for hydrocarbon oils and their decomposition products, and of the class consisting of kerosene and gas oil in which has been incorporated a minor percentage of an oil soluble metalloorganic derivative of an element of the group consisting of lead, bismuth, arsenic, antimony, tin and zinc.

4. A flushing oil comprising a petroleum oil solvent for hydrocarbon oils and their decomposition products, and of the class consisting of kerosene and gas oil, in which has been incorporated a minor percentage of a metallic engine conditioning agent selected from the group consisting of colloidal metals and metallo-organic compounds.

5. A flushing oil according to claim 4 in which the metallic engine conditioning agent is co]- loidal lead.

. ROBERT P. RUSSELL. 

